Elongated convenience outlet with continuous slot



June 1, 1954 w. M FARLIN 2,680,233

ELONGATED CONVENIENCE OUTLET WITH CONTINUOUS SLOT Filed Sept. 26, 1950 I INVENTORK .8 Passer W. No F404 AM,AM*M

A TTOEA/E Y5 Patented June 1, 1954 UNITED STATES PATENT OFFICE ELONGATED CONVENIENCE OUTLET WITH CONTINUOUS SLOT Robert W. McFarlin, Milwaukee, Wis.

Application September 26, 1950, Serial No. 186,821

10 Claims.

This invention relates to an electrical convenience outlet which is continuous in the sense that electrical lamps or appliances may be plugged into it at any point throughout its length, the slots for receiving the prongs of the connector plugs being continuous and the device being not merely elongated but adapted for rectilinear or angular connection to other similar outlet devices.

It isa primary object of the invention to provide a simple and inexpensive device of the type indicated. I am aware that others have sought to provide convenience outlets with continuous slots but they have all been relatively complex devices. It is one of the major purposes of the present invention to use for the purposes of the present device an extruded molding which may be cut in any desired length and to the ends of which end caps are applicable to confine the bus bars and contacts within the. molding. In this connection, it is a further important object of the invention to provide bus bar contacts which need not have any physical connection with the molding other than merely to be confined therein, the shape of the molding being such that the metal parts may be inserted through the open end thereof and will be retained by the mere application of the end cap to the molding.

Another object of the invention is to provide a device of this character which may be embodied in the plaster, screwed on the wall or the fioor, or left free at the end of an extension cord, as may be desired, or which may be connected through the use of simple fittings either in alignment with similar devices or at right angles thereto for extension around an inside or outside corner.

In a device of this character, a great problem has been the provision of contact means within the outlet housing which would remain resiliently effective to provide adequate electrical contact with theprongs of any number of electrical plugs, regardless of the locations of such plugs. For example, where three plugs are located close together, it is always a problem to assure an adequate electrical connection to the prongs of the middle plug in the series, since the contact means tends to be deflected by the prongs of the end plugs in the series and thereby to be forced out of contact with the prongs of the middle plug. Through the means hereinafter to be disclosed, I have solved this problem by the provision of a combination contact and bus bar means which provides adequate current carrying capacity with a 'highdegree-of flexibility and'resilience soas to 2 assure proper contact regardless of the number or location of the prongs engaged therewith.

The present application is a continuation in part of my application Serial No. 104,747, filed July 14, 1949, now abandoned.

In the drawings:

Fig. 1 is a view in perspective iragmentarily showing acomplete unit embodying my invention as it appears when applied to a wall adjacent the baseboard.

Fig. 2 is a view in perspective fragmentarily showing one end of my improved unit as it appears with one of the end caps removed and the bus bar and contact elements partially withdrawn.

Fig. 3 is a detail View on a greatly enlarged scale in transverse cross section through the device as it appears when an electrical attachment plug is engaged therein.

Fig. 4 is a detail view taken on the line 4-4 of Fig. 1.

Fig. 5 is a detail view taken on the line 5-5 of Fig. 1.

Fig. 6 is a detail view in perspective of one of the end caps.

Fig. 7 is a detail view in perspective showing a duplex end cap and electrical connector which is used between two successive aligned units embodying my invention.

Fig. 8 is a detail view partially in plan and p tially in section through an outside corner coupler.

Fig. 9 is a view similar to Fig. 8 through an inside corner coupler.

Fig. 10 is a view taken in section on the line iil|ll ofFig. 3.

As already indicated, the housing for the contact elements used in my improved outlet device desirably comprises a continuous piece of extrudedplastic-molding. This molding comprises in one piece an elongated central boss II having at intervals screw holes 12 for. receiving screws I3 by which it may be connected to any suitable surface I 4 as indicated in Fig. 3.

The boss I I is formed by a web which connects two channels l5 and I6, each of which has a bottom wall at I I to engage the surface IS, an outer wall I8,w.hich may desirably be somewhat inwardly concave, as shown in Fig. 3, and an inwardly turned flange l9 which approaches very closely to the inner wall which is common to the channel and to the central boss I I.

.iBe-tween the central boss and the inwardly turned flanges I9 arethe continuous slots 20-and 2| through which may be inserted the prongs 46. 46, of the appliance plug 41. Since the slots 20 and 2| are continuous throughout the length of the molding between the end caps hereinafter to be described, the number of positions at which a given plug may be located is infinite.

At each end of the molding is an end cap 25. v

and the side walls 28 and 2S engage the 0011- cave outer sides of the channels. The rib 30 engages the top of the elongated boss I l as is clearly shown in Fig. l. The end caps, or at least one of them, is apertured at a l, 32 to receive th conductors 35 which, connected with another plug at 35, receive current from the regular convenience outlet 36, and carry such current to the conductors which are housed within the extruded plastic molding above described.

Extending substantially the full length of the extended molding and inserted endwise into the respective channels thereof are two bus bars and contact conductors 43, each of which is bent on longitudinal lines at ii, 42 whereby the conductor comprises three well-defined strips 43, 44 and 45, the strip 53 and the strip M being substantially parallel and offset, and the intervening strip extending obliquely between strips 43, 44 to present a zig-zag pattern as clearly appears in Figs. 2 and 3.

The conductor is desirably made of .008 to .012 inch sheet copper of the grade of hardness known as half-hard. Such a conductor is large enough to carry the required current and resilient enough to deflect readily when engaged by the contact prong of an appliance plug. However, du to the form of the conductor and its degree of flexibility, such deflection will be localized in the immediate vicinity of the prong of an inserted plug and will tend to occur in such fashion that the portion of strip 44 engaged by the prong will lie in full face contact therewith.

The width of the bus bar conductor is desirably such that free margin of its portion 43 is engaged within the biglit of the reversely bent flange 19 at the top of the channel, while the free margin of the conductor portion M is engaged with the bottom of the channel as clearly appears in Fig. 3. In other words, the overall width of the bus bar dd substantially corresponds to the depth of the channel.

The form of the bus bar in cross section is such that the apex at il engages the inner surface of the outer wall [8 of the plastic channel, the angle of the portion 45 of the conductor being such as to turn to force the apex 42 and the portion M of the conductor against the inner wall lb or Itof the channel. When the prongs 46 of an appliance plug 'l are inserted as shown in Figs. 3 and 10, they force aside a local area of strip 4 5 of the conductor 4%, increasing the thrust of the conductor at apex 4| upon the wall portion it of the channel.

After experimenting with many different shapes and styles of conductors, I have found that the zigzag shape above described is the only one which gives adequate electrical contact with the several. rongs of appliance plugs which are in immediate proximity as shown in Fig. 10, the deflection being localized at each prong so that no matter how close together the prongs may be, each will receive adequate contact, the contact usually being the desired face contact which affords relatively large contact area.

The ends of the conductors 33 and 34 are desirably soldered to the respective bus bars 40 as shown in Fig. 2. Th mechanical assembly is then completed by sliding the end cap on to the end of the extruded molding and fastening it by a screw 48 in Fig. 2.

Where more than one length of molding is desired, a plurality of lengths can be connected by the connector caps or fittings shown in Figs, 7, 8 and 9. If the moldings are to be aligned, the fitting of Fig. 7 is employed. This fitting 250 has the form of two of the fittings 25 shown in Fig. 7 connected back to back, the only change being the provisions of conductors 49 and 50 which are molded into a central partition wall 210 to project at each side in spaced relation to the bosses 290, so that the conductors t9 and 50 are receivable into the channels of both of the outlet moldings for frictional electrical contact with the bus bars in the respective moldings.

The fittings shown in Figs. 8 and 9 are identical except that they are respectively designed for outside and inside corners. In each case, the shell of the fitting serves as an end cap for each of the moldings to which it is mechanically connected and in each case the fitting includes conductors which make electrical connection between the bus bars of the respective moldings.

I claim:

1. An electrical convenience outlet to receive the prong of an appliance plug, said outlet comprising a casing internally providing a contact chamber and having a prong-insertion slot and an adjacent blind channel both opening into said chamber, a resilient contact element disposed in the chamber and having one marginal portion anchored in the channel and an opposite free marginal portion disposed obliquely across the path of prong insertion, the said casing having fulcrum means opposite the contact element at a point intermediate said marginal portions, and the said contact element having an intermediate portion engaged with said fulcrum means to support its free marginal portion yieldably in the path of an inserted prong, the said casing chamber having sufiicient capacity to accommodate the yielding of said fre marginal portion when the later is displaced by an inserted p n 2. The device of claim 1 in which the said marginal portions of said resilient contact are laterally ofiset, the said intervening portion of the contact extending therebetween.

3. The device of claim 2 in which the said casing has a wall portion convexly extending into said chamber to provide the fulcrum means aforesaid, the contact element engaging the inwardly convex wall adjacent the juncture between its intermediate portion and its anchored marginal portion.

4. An electrical convenience outlet having elongated slots for receiving the prongs of an appliance plug at selected positions within the length of the slots, said outlet comprising a casing having a transverse spacing web and a pair of channels-integrally connected therewith and each provided with inner and outer walls spaced to afford contact chambers extending longitudinally of the casing, theouter walls having integral closure elements extending toward the web first mentioned and constituting shallow channels opening into the respective chambers, the said closure elements being spaced from the inner walls of said channels to provide prong receiving slots, together with resilient strip contact elements having their outer edges respectively confined in the channels of the closure elements and having free edges in the respective contact chambers in immediate proximity to the inner walls thereof, the said free edges projecting across the paths of prong insertion through said slots into said chambers to assure contact between the prongs and the respective elements, each of said elements and the outer walls of the respective chambers having portions in thrust engagement from which other portions of the contact elements extend obliquely toward the inner walls of the respective chambers, the free edges adjacent such walls being relatively yieldable toward the outer walls of the contact chambers under thrust of inserted prongs, the space between the inner and outer walls in proximity to the free edges of said contact elements being sufiicient to accommodate the outward yielding of the free edges of such elements.

5. The combination set forth in claim 4 in which the outer walls of the contact chambers are inwardly convex to assure the said engagement with the intermediate portions of the respective contact elements.

6. An electric convenience gated slots to receive the pl outlet having elonprongs of an appliance said outlet comprising elongated parallel channels having inner and outer walls, an integral web connecting the inner walls, a closure integral with the outer walls of said channels and comprising intermediate walls directed into said channels and cooperating with the outer walls to provide contact anchorage channels, elongated flexible contact strips having anchored edge portions fixed in the anchorage channels and having free edge portions disposed in the channels first mentioned, the prongs of an appliance plug being receivable between the intermediate and inner walls aforesaid upon paths in which the free edges of the respective contact strips are disposed, the said contact strips and the said outer walls respectively having intermediate portions in mutual thrust engagement supporting free edges of said strips yieldably in the paths of said prongs, said channels being sufficiently wide at their bases to accommodate yielding of free edge portions of said strip under thrust of inserted prongs.

7. The combination set forth in claim 6 in which each of said contact strips comprises laterally offset edge portions and an obliquely extending intermediate portion, the engagement of said intermediate portion with the outer wall of the corresponding channel being adjacent its connection with the anchored edge portion of the strip.

8. The combination set forth in claim 6 in which the outer wall of each channel is inwardly convex to provide a fulcrum over which the intermediate portion of the strip is yieldable while aifording channel width below said intermediate portion to accommodate the yielding of free edge portions of the strip engaged by said prong.

9. In a continuous outlet device of the character described for receiving the contact prongs of appliance plugs, the combination with a channel of insulating material having one side closed and an opposite side provided with pocket forming means partially closing the channel and leaving a slot for the reception of a contact prong, of

an elongated contact strip of resiliently flexible material substantially corresponding in depth to the channel and having one of its margins engaged in pocket forming means and the other free in the closed side of the channel, the respective margins of said strip being mutually ofiset and connected by an integral intermediate portion of said strip, the strip being in lateral thrust engagement with the outside of the channel substantially along the line upon which its said intermediate portion joins with its first mentioned margin, said intermediate portion extending thence across the channel and its free margin being thereby positioned in the path of an inserted prong.

10. The device of claim 9 wherein the respective margins of said strip are substantially planiform and the intermediate portion extends angularly therebetween.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,846,462 Turner Feb. 23, 1932 1,955,168 Beersman Apr. 1'7, 1934 1,964,042 Du Bois June 24, 1934 2,028,009 Plante Jan. 14, 1936 2,064,199 Elder Dec. 15, 1936 2,361,721 Van Deventer Oct. 31, 1944 

